J/ApJ/900/14 ∼17000 runaways stars from the Orion Nebula Cluster (Farias+, 2020)
Hunting for Runaways from the Orion Nebula Cluster.
Farias J.P., Tan J.C., Eyer L.
<Astrophys. J., 900, 14 (2020)>
=2020ApJ...900...14F 2020ApJ...900...14F
ADC_Keywords: Clusters, open; Positional data; Radial velocities
Keywords: Astrometry ; Stellar kinematics ; Young star clusters ;
Stellar dynamics ; Star formation ; Runaway stars
Abstract:
We use Gaia DR2 to hunt for runaway stars from the Orion Nebula
Cluster (ONC). We search a region extending 45° around the ONC and
out to 1 kpc to find sources that have overlapped in angular position
with the cluster in the last ∼10Myr. We find ∼17000 runaway/walkaway
candidates that satisfy this 2D traceback condition. Most of these are
expected to be contaminants, e.g., caused by Galactic streaming
motions of stars at different distances. We thus examine six further
tests to help identify real runaways, namely: (1) possessing young
stellar object (YSO) colors and magnitudes based on Gaia optical
photometry; (2) having IR excess consistent with YSOs based on 2MASS
and Wide-field Infrared Survey Explorer photometry; (3) having a high
degree of optical variability; (4) having closest approach distances
well-constrained to within the cluster half-mass radius; (5) having
ejection directions that avoid the main Galactic streaming
contamination zone; and (6) having a required radial velocity (RV) for
3D overlap of reasonable magnitude (or, for the 7% of candidates with
measured RVs, satisfying 3D traceback). Thirteen sources, not
previously noted as Orion members, pass all these tests, while another
twelve are similarly promising, except they are in the main Galactic
streaming contamination zone. Among these 25 ejection candidates, ten
with measured RVs pass the most restrictive 3D traceback condition. We
present full lists of runaway/walkaway candidates, estimate the
high-velocity population ejected from the ONC, and discuss its
implications for cluster formation theories via comparison with
numerical simulations.
Description:
Using the unprecedented astrometric accuracy of Gaia DR2, we have
examined a wide region extending out to 45deg around the Orion Nebula
Cluster (ONC) to search for runaway (or walkaway) stars it may have
produced. Within this area, we have selected 16994 sources that have a
2D trajectory in the sky that brings them back to the ONC in the
recent past.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 636 16994 Full sample of ONC's runaway candidates traced back
in 2D
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See also:
II/332 : c2d Spitzer final data release (DR4) (Evans+, 2003)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
II/360 : Gaia DR2 x AllWISE catalogue (Marton+, 2019)
J/AcA/48/35 : All Sky Automated Survey variable stars (Pojmamski 1998)
J/AJ/119/3026 : Circumstellar disk candidates in Orion (Rebull+, 2000)
J/A+A/502/883 : photometry very low mass ONC stars (Rodriguez-Ledesma+, 2009)
J/ApJ/722/1092 : Optical photometry of the ONC. II. (Da Rio+, 2010)
J/AJ/144/192 : Spitzer survey of Orion A & B. I. YSO catalog (Megeath+, 2012)
J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)
J/ApJ/818/59 : IN-SYNC. IV. YSOs in Orion A (Da Rio+, 2016)
J/ApJS/229/28 : SFiNCs: X-ray, IR and membership catalogs (Getman+, 2017)
J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018)
J/AJ/156/271 : The stellar membership of the Taurus SFR (Luhman, 2018)
J/A+A/620/A172 : Solar neighbourhood young stars 3D mapping (Zari+, 2018)
J/A+A/627/A57 : ONC binary and triple stars (Jerabkova+, 2019)
J/AJ/157/109 : Stellar proper motions in the Orion Nebula Cluster (Kim+,2019)
J/ApJ/870/32 : Kinematics in young star clusters & associations (Kuhn+, 2019)
J/ApJ/884/6 : Known members of Orion A with Gaia DR2 data (McBride+, 2019)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- Gaia Gaia DR2 source identifier
21- 29 A9 --- Label Source label and score; see Sec. 5.1
31- 48 F18.14 deg GLON [160/258] Gaia DR2 Galactic longitude (J2015.5)
50- 71 F22.18 deg GLAT [-64.3/24.6] Gaia DR2 Galactic latitude
(J2015.5)
73- 92 F20.16 pc dONC [0.36/738] 3D distance to the ONC
94-115 F22.19 deg theta [0.002/45.2] Angular distance to the ONC
117-138 F22.18 km/s vt0 [0.06/605] Transverse velocity in the ONC frame
140-161 F22.19 Myr tback [0.001/40.7] 2D traceback time
163-188 F26.18 km/s vrOpt [-160584/53149] Median optimal radial velocity
190-216 F27.19 km/s b_vrOpt [-161544/30219] The 16th percentile uncertainty
in vrOpt
218-244 F27.19 km/s B_vrOpt [-159682/118973] The 84th percentile
uncertainty in vrOpt
246-269 F24.19 km/s RVel [-133/296]? Gaia DR2 radial velocity
271-290 F20.17 km/s e_RVel [0.1/18]? Uncertainty in RVel
292-314 F23.20 --- Vi [-0.91/5.45]? Intrinsic variability; see
Sec. 4.3
316-337 F22.19 arcmin Dmin [0.001/68.2] Closest approach ONC; 2D traceback
339-360 F22.18 arcmin e_Dmin [0.01/852] Uncertainty in Dmin
362-382 F21.17 deg PA [0.08/360] Position Angle from the ONC
384-402 F19.17 --- R [0.114/0.95]? Probability being real source (1)
404-425 F22.20 --- SY [0/1]? YSO proba. using 2 AllWISE bands (1)
427-448 F22.20 --- LY [0/1]? YSO proba. using 4 AllWISE bands (1)
450-468 F19.15 pc d [6.42/1000] Gaia DR2 parallax distance
470-489 F20.15 pc E_d [6.42/1245] Upper uncertainty in d
491-509 F19.15 pc e_d [6.41/982] Lower uncertainty in d
511-530 F20.16 km/s v3DONC [2.57/410]? Space velocity in ONC frame of
reference
532-553 F22.18 Myr tback3D [-26.9/19.4]? 3D traceback time
555-576 F22.19 Myr e_tback3D [0.003/11]? Uncertainty in tback3D
578-598 F21.17 pc dmin3D [0.2/641]? Closest approach to ONC 3D traceback
600-618 F19.16 pc e_dmin3D [0.5/91]? Uncertainty in dmin3D
620-621 I2 --- YSOFlag [-1/1] YSO flag: +1 pass, -1 fail
623-624 I2 --- WYSOFlag [-1/1] WYSO flag: +1 pass, -1 fail, 0 not
evaluated
626-627 I2 --- VARFlag [-1/1] VAR flag: +1 pass, -1 fail, 0 not
evaluated
629-630 I2 --- CAFlag [-1/1] CA flag: +1 pass, -1 fail
632-633 I2 --- PAFlag [-1/1] PA flag: +1 pass, -1 fail
635-636 I2 --- RVFlag [-1/1] RV flag: +1 pass, -1 fail
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Note (1): From Marton+, 2019MNRAS.487.2522M 2019MNRAS.487.2522M.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 28-Oct-2021